The present invention relates generally to needle assemblies, and in particular, to a needle assembly that utilizes a retractable sheath that is retractably slidable relative to the cannula such that the cannula is exposed when the sheath is in its retracted position and the cannula can be reencased by the sheath when it is repositioned in its non-retracted position. Advantageously, the sheath can be repositioned in its non-retracted position using only one hand.
Needle assemblies for use in medical procedures or operations in which blood or other fluids must be drawn from a patient or injected into a patient, or in which bone, tissue or tumors are removed, or in which catheters (or the like) are positioned in a body are well known, and are described in issued patents such as U.S. Pat. Nos. 4,713,061 and 4,240,423. At least one of these patents, U.S. Pat. No. 4,713,061, recognizes the need to protect the doctor (or other authorized medical personnel) from being inadvertently xe2x80x9cstuckxe2x80x9d by the needle (or cannula) by its description of what appears to be a removable xe2x80x9cneedle shield.xe2x80x9d
Unfortunately, the present state of the art is deficient in this regard. For example, because most known xe2x80x9cneedle shieldsxe2x80x9d are removable, the needle is dangerously exposed after it is used. This leaves open the possibility that the needle can still cause an undesirable xe2x80x9cpokingxe2x80x9d or xe2x80x9csticking.xe2x80x9d Therefore, a needle guard or shield that is easily replaceable over the needle is desired. However, this is only one part of the prior art""s deficiency since the shield or guard would still require two hands to be replaced back on the needle assembly, as one hand would inevitably be needed to hold the hub (with the needle) as the other hand is used to grasp and replace the shield/guard. In today""s stringent medical procedures and requirements, a one-handed method for securing the shield/guard back on the needle assembly is necessary and desired.
Accordingly, it is desirable to provide an improved needle assembly that overcomes the perceived deficiencies in the prior art noted above and further achieves the aforementioned and below mentioned objectives; namely, a needle assembly that can be used by medical personnel or other appropriate/necessary users, and that is both effective and protective of everyone that would handle the assembly and for which the covering of the needle after use can be achieved with one hand, if desired.
Generally speaking, in accordance with the present invention, an improved needle assembly is provided. In a preferred embodiment, the needle assembly comprises a hub, the hub comprising a body portion with an internal hollow region in which fluid is one of collected or discharged and a neck portion having a bore therethrough that opens at a first end thereof into the hollow region in the body portion; a cannula coupleable to the hub in which a first end of the cannula is inserted into the other end of the bore of the neck portion; and a retractable sheath comprising a tubular portion, the tubular portion being slideably mounted about the neck portion, the cannula being at least substantially encaseable along at least a substantial length thereof by the tubular portion; wherein the tubular portion of the sheath is retractably slidable about the neck portion and along at least the substantial length of the cannula such that (a) at least a length of the cannula extending outwardly from the bore is exposed when the sheath is in its retracted position and (b) the length of the cannula extending outwardly from the bore is at least essentially encased when the sheath is in it non-retracted position.
In a preferred construction, the tubular portion may be configured so as to xe2x80x9csplitxe2x80x9d down a substantial length thereof when the sheath is retracted about the neck portion and along a length of the cannula. For this purpose, the tubular portion may include a groove along a length thereof, the existence of the groove for facilitating the splitting of the tubular portion down a length thereof when the sheath is retracted about the neck portion and along a length of the cannula. The tubular portion preferably also has a portion without any groove to prevent the sheath from uncoupling from its engagement with the neck portion of the hub when the sheath is in its fully retracted position.
The hub may include a channel for channeling the tubular portion along the neck portion and away from the hub as the sheath is retracted about the neck portion and along the length of the cannula. A sleeve may be provided on the hub body and spaced apart from the neck portion so as to allow the tubular portion of the sheath to be slidably mounted on the neck portion intermediate the neck portion and the sleeve to further guide the sheath as it is being retracted about the neck portion and along a length of the cannula.
Stop-tabs and stop-lugs may be provided on the sleeve and sheath, respectively, for preventing the sheath from oversliding about the length of the cannula when the sheath is sliding from its retracted position to its non-retracted position.
The present invention also provides a method of using the aforementioned needle assembly construction, in which the method comprises the steps of retracting the sheath about the neck portion and along the cannula such that at least a portion of the cannula extending outwardly from the bore is exposed when the sheath is in its retracted position; and repositioning the sheath along the length of the cannula such that the cannula is essentially encased. In accordance with the present invention, the step of repositioning the sheath about the cannula may be achieved with one hand.
In an alternate embodiment which is also fully supported by the following detailed description, the needle assembly may more generally be seen to comprise a hub, the hub itself comprising a body portion and a neck portion coupled to the body portion; a cannula coupleable to the hub in which a first end of the cannula is coupled to or inserted in the neck portion; and a retractable sheath comprising a tubular portion, the tubular portion being slideably mounted about the neck portion, the cannula being at least substantially encaseable along at least a substantial length thereof by the tubular portion; wherein the tubular portion of the sheath is retractably slidable about the neck portion and along at least the substantial length of the cannula such that (a) at least a second end of the cannula is exposed when the sheath is in its retracted position and (b) the second end of the cannula is covered when the sheath is in it non-retracted position. This alternate embodiment is similar to the aforementioned embodiment although this alternate embodiment need not be used for the receipt or discharge of fluids; that is, such an embodiment may be utilized for the collection of tissue, bone, tumors or the like in a manner as would be understood in the art. Also, it should be understood throughout the application that the word xe2x80x9cencasedxe2x80x9d should be understood to be synonymous with xe2x80x9ccoveredxe2x80x9d so as to be clear that the tip of the cannula need not be fully encased, but rather only covered as illustrated in the figures. A method of using this alternative embodiment is also disclosed in which the method comprises the steps of retracting the sheath about the neck portion and along the cannula such that the second end of the cannula is exposed when the sheath is in its retracted position; and repositioning the sheath along the substantial length of the cannula such that the second end of the cannula is at least essentially covered. It should also be understood that the subject matter that is recited in all the dependant claims set forth herein are equally utilizable with this alternate embodiment. That is, the features of the retractable sheath are equally applicable regardless of the particular construction of the hub and cannula as long as the construction provides for the retractability of the sheath as set forth below.
Accordingly, it is an objective of the present invention to provide an improved needle assembly construction.
Another objective of the present invention is to provide an improved needle assembly that is safer to use by way of its inclusion of a retractable sheath for encasing or otherwise covering the cannula.
Yet another objective of the present invention is to provide an improved needle assembly that includes a retractable sheath that can be repositioned over the cannula after use, all while using only one hand.
Still another objective of the present invention is to provide an improved needle assembly that achieves all of the aforementioned objectives that is both easy and inexpensive to manufacture.
Still another objective of the present invention is to provide a method of using a needle assembly constructed in accordance with the present invention.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.
The invention accordingly comprises the features of construction, combination of elements and arrangement of parts and sequence of steps which will be exemplified in the construction, illustration and description hereinafter set forth, and the scope of the invention will be indicated in the claims.